1
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Otte KA, Fredericksen M, Fields P, Fröhlich T, Laforsch C, Ebert D. The cuticle proteome of a planktonic crustacean. Proteomics 2024; 24:e2300292. [PMID: 38676470 DOI: 10.1002/pmic.202300292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 04/29/2024]
Abstract
The cuticles of arthropods provide an interface between the organism and its environment. Thus, the cuticle's structure influences how the organism responds to and interacts with its surroundings. Here, we used label-free quantification proteomics to provide a proteome of the moulted cuticle of the aquatic crustacean Daphnia magna, which has long been a prominent subject of studies on ecology, evolution, and developmental biology. We detected a total of 278 high-confidence proteins. Using protein sequence domain and functional enrichment analyses, we identified chitin-binding structural proteins and chitin-modifying enzymes as the most abundant protein groups in the cuticle proteome. Structural cuticular protein families showed a similar distribution to those found in other arthropods and indicated proteins responsible for the soft and flexible structure of the Daphnia cuticle. Finally, cuticle protein genes were also clustered as tandem gene arrays in the D. magna genome. The cuticle proteome presented here will be a valuable resource to the Daphnia research community, informing genome annotations and investigations on diverse topics such as the genetic basis of interactions with predators and parasites.
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Affiliation(s)
- Kathrin A Otte
- Institute of Cell and Systems Biology of Animals, University of Hamburg, Hamburg, Germany
| | - Maridel Fredericksen
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Peter Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
| | - Thomas Fröhlich
- Laboratory for Functional Genome Analysis, Gene Center, LMU Munich, Munich, Germany
| | | | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
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2
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Rand DM, Nunez JCB, Williams S, Rong S, Burley JT, Neil KB, Spierer AN, McKerrow W, Johnson DS, Raynes Y, Fayton TJ, Skvir N, Ferranti DA, Zeff MG, Lyons A, Okami N, Morgan DM, Kinney K, Brown BRP, Giblin AE, Cardon ZG. Parasite manipulation of host phenotypes inferred from transcriptional analyses in a trematode-amphipod system. Mol Ecol 2023; 32:5028-5041. [PMID: 37540037 PMCID: PMC10529729 DOI: 10.1111/mec.17093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 07/21/2023] [Accepted: 07/25/2023] [Indexed: 08/05/2023]
Abstract
Manipulation of host phenotypes by parasites is hypothesized to be an adaptive strategy enhancing parasite transmission across hosts and generations. Characterizing the molecular mechanisms of manipulation is important to advance our understanding of host-parasite coevolution. The trematode (Levinseniella byrdi) is known to alter the colour and behaviour of its amphipod host (Orchestia grillus) presumably increasing predation of amphipods which enhances trematode transmission through its life cycle. We sampled 24 infected and 24 uninfected amphipods from a salt marsh in Massachusetts to perform differential gene expression analysis. In addition, we constructed novel genomic tools for O. grillus including a de novo genome and transcriptome. We discovered that trematode infection results in upregulation of amphipod transcripts associated with pigmentation and detection of external stimuli, and downregulation of multiple amphipod transcripts implicated in invertebrate immune responses, such as vacuolar ATPase genes. We hypothesize that suppression of immune genes and the altered expression of genes associated with coloration and behaviour may allow the trematode to persist in the amphipod and engage in further biochemical manipulation that promotes transmission. The genomic tools and transcriptomic analyses reported provide new opportunities to discover how parasites alter diverse pathways underlying host phenotypic changes in natural populations.
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Affiliation(s)
- David M Rand
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island, USA
| | - Joaquin C B Nunez
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Shawn Williams
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Stephen Rong
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island, USA
| | - John T Burley
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
- Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
| | - Kimberly B Neil
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Adam N Spierer
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Wilson McKerrow
- Division of Applied Mathematics, Brown University, Providence, Rhode Island, USA
| | - David S Johnson
- Department of Biological Sciences, Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, USA
| | - Yevgeniy Raynes
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Thomas J Fayton
- University of Southern Mississippi, Hattiesburg, Mississippi, USA
- Cornell University, Ithaca, New York, USA
| | - Nicholas Skvir
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - David A Ferranti
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Maya Greenhill Zeff
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Amanda Lyons
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - Naima Okami
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | - David M Morgan
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
| | | | - Bianca R P Brown
- Department of Ecology, Evolution and Organismal Biology, Brown University, Providence, Rhode Island, USA
- Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
| | - Anne E Giblin
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
| | - Zoe G Cardon
- Ecosystems Center, Marine Biological Laboratory, Woods Hole, Massachusetts, USA
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3
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Byrnes I, Rossbach LM, Brede DA, Grolimund D, Ferreira Sanchez D, Nuyts G, Čuba V, Reinoso-Maset E, Salbu B, Janssens K, Oughton D, Scheibener S, Teien HC, Lind OC. Synchrotron-Based X-ray Fluorescence Imaging Elucidates Uranium Toxicokinetics in Daphnia magna. ACS NANO 2023; 17:5296-5305. [PMID: 36921214 PMCID: PMC10062025 DOI: 10.1021/acsnano.2c06111] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 03/13/2023] [Indexed: 06/17/2023]
Abstract
A combination of synchrotron-based elemental analysis and acute toxicity tests was used to investigate the biodistribution and adverse effects in Daphnia magna exposed to uranium nanoparticle (UNP, 3-5 nm) suspensions or to uranium reference (Uref) solutions. Speciation analysis revealed similar size distributions between exposures, and toxicity tests showed comparable acute effects (UNP LC50: 402 μg L-1 [336-484], Uref LC50: 268 μg L-1 [229-315]). However, the uranium body burden was 3- to 5-fold greater in UNP-exposed daphnids, and analysis of survival as a function of body burden revealed a ∼5-fold higher specific toxicity from the Uref exposure. High-resolution X-ray fluorescence elemental maps of intact, whole daphnids from sublethal, acute exposures of both treatments revealed high uranium accumulation onto the gills (epipodites) as well as within the hepatic ceca and the intestinal lumen. Uranium uptake into the hemolymph circulatory system was inferred from signals observed in organs such as the heart and the maxillary gland. The substantial uptake in the maxillary gland and the associated nephridium suggests that these organs play a role in uranium removal from the hemolymph and subsequent excretion. Uranium was also observed associated with the embryos and the remnants of the chorion, suggesting uptake in the offspring. The identification of target organs and tissues is of major importance to the understanding of uranium and UNP toxicity and exposure characterization that should ultimately contribute to reducing uncertainties in related environmental impact and risk assessments.
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Affiliation(s)
- Ian Byrnes
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Lisa Magdalena Rossbach
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Dag Anders Brede
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Daniel Grolimund
- Swiss
Light Source, Paul Scherrer Institute (PSI), 5232 Villigen, Switzerland
| | | | - Gert Nuyts
- AXIS
Group, NANOlab Center of Excellence, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Václav Čuba
- Faculty
of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Brehova 7, 166 36 Prague 1, Czech Republic
| | - Estela Reinoso-Maset
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Brit Salbu
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Koen Janssens
- AXIS
Group, NANOlab Center of Excellence, Department of Physics, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Deborah Oughton
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Shane Scheibener
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Hans-Christian Teien
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
| | - Ole Christian Lind
- Centre
for Environmental Radioactivity (CERAD), Faculty of Environmental
Sciences and Natural Resource Management, Norwegian University of Life Sciences, P.O. Box 5003, 1433 Ås, Norway
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4
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Marcus E, Dagan T, Asli W, Ben-Ami F. Out of the 'host' box: extreme off-host conditions alter the infectivity and virulence of a parasitic bacterium. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220015. [PMID: 36744562 PMCID: PMC9900709 DOI: 10.1098/rstb.2022.0015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 12/24/2022] [Indexed: 02/07/2023] Open
Abstract
Disease agents play an important role in the ecology and life history of wild and cultivated populations and communities. While most studies focus on the adaptation of parasites to their hosts, the adaptation of free-living parasite stages to their external (off-host) environment may tell us a lot about the factors that shape the distribution of parasites. Pasteuria ramosa is an endoparasitic bacterium of the water flea Daphnia with a wide geographical distribution. Its transmission stages rest outside of the host and thus experience varying environmental regimes. We examined the life history of P. ramosa populations from four environmental conditions (i.e. groups of habitats): the factorial combinations of summer-dry water bodies or not, and winter-freeze water bodies or not. Our goal was to examine how the combination of winter temperature and summer dryness affects the parasite's ability to attach to its host and to infect it. We subjected samples of the four groups of habitats to temperatures of 20, 33, 46 and 60°C in dry and wet conditions, and exposed a susceptible clone of Daphnia magna to the treated spores. We found that spores which had undergone desiccation endured higher temperatures better than spores kept wet, both regarding attachment and subsequent infection. Furthermore, spores treated with heightened temperatures were much less infective and virulent. Even under high temperatures (60°C), exposed spores from all populations were able to attach to the host cuticle, albeit they were unable to establish infection. Our work highlights the sensitivity of a host-free resting stage of a bacterial parasite to the external environment. Long heatwaves and harsh summers, which are becoming more frequent owing to recent climate changes, may therefore pose a problem for parasite survival. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- Enav Marcus
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Tal Dagan
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Weaam Asli
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 6997801, Israel
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5
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Bacterial ectosymbionts in cuticular organs chemically protect a beetle during molting stages. THE ISME JOURNAL 2022; 16:2691-2701. [PMID: 36056153 PMCID: PMC9666510 DOI: 10.1038/s41396-022-01311-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 08/11/2022] [Accepted: 08/17/2022] [Indexed: 12/15/2022]
Abstract
In invertebrates, the cuticle is the first and major protective barrier against predators and pathogen infections. While immune responses and behavioral defenses are also known to be important for insect protection, the potential of cuticle-associated microbial symbionts to aid in preventing pathogen entry during molting and throughout larval development remains unexplored. Here, we show that bacterial symbionts of the beetle Lagria villosa inhabit unusual dorsal invaginations of the insect cuticle, which remain open to the outer surface and persist throughout larval development. This specialized location enables the release of several symbiont cells and the associated protective compounds during molting. This facilitates ectosymbiont maintenance and extended defense during larval development against antagonistic fungi. One Burkholderia strain, which produces the antifungal compound lagriamide, dominates the community across all life stages, and removal of the community significantly impairs the survival probability of young larvae when exposed to different pathogenic fungi. We localize both the dominant bacterial strain and lagriamide on the surface of eggs, larvae, pupae, and on the inner surface of the molted cuticle (exuvia), supporting extended protection. These results highlight adaptations for effective defense of immature insects by cuticle-associated ectosymbionts, a potentially key advantage for a ground-dwelling insect when confronting pathogenic microbes.
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6
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Lind CM, Agugliaro J, Lorch JM, Farrell TM. Ophidiomycosis is related to seasonal patterns of reproduction, ecdysis, and thermoregulatory behavior in a free‐living snake species. J Zool (1987) 2022. [DOI: 10.1111/jzo.13024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | | | - J. M. Lorch
- U.S. Geological Survey ‐ National Wildlife Health Center Madison WI USA
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7
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Świsłocka M, Ratkiewicz M, Borkowska A. Simultaneous Infection of Elaphostrongylus Nematode Species and Parasite Sharing between Sympatrically Occurring Cervids: Moose, Roe Deer, and Red Deer in Poland. Pathogens 2021; 10:1344. [PMID: 34684292 PMCID: PMC8540609 DOI: 10.3390/pathogens10101344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/08/2021] [Accepted: 10/15/2021] [Indexed: 11/17/2022] Open
Abstract
It is important to assess the distribution of parasite species across wildlife populations, to design strategies for game management and effective disease control in nature. In this project we quantified the prevalence of Elaphostrongylus species in eight moose populations. We used molecular methods for identification of parasite species and host individual genotypes from fecal samples. We also demonstrated sharing of parasite species between three cervid hosts sympatrically occurring in the Biebrza River valley, North-Eastern Poland, which is occupied by the largest autochthonous, non-harvested moose population in Central Europe. Nematode species from the genus Elaphostrongylus are ubiquitous in the studied moose populations. The presence of a single parasite species (e.g., E. alces) in moose individuals was more common than simultaneous infection with E. alces and E. cervi. The prevalence of both E. alces and E. cervi was higher in males than females. The distribution of E. alces and E. cervi prevalence in moose, roe deer, and red deer were in accordance with the membership of a host to a subfamily. Simultaneous occurrences of both Elaphostrongylus species were significantly more frequently noted in red deer fecal samples than those collected from moose or roe deer. Thus, we consider red deer to play a dominant role in sharing of those nematodes to other cervids. Our findings promote applications of molecular methods of identifying parasite species and the assessment of the exchange of parasite community between wild ruminant species in management and health monitoring of game animal populations.
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Affiliation(s)
- Magdalena Świsłocka
- Department of Zoology and Genetics, Faculty of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland; (M.R.); (A.B.)
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8
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Kruppert S, Chu F, Stewart MC, Schmitz L, Summers AP. Ontogeny and potential function of poacher armor (Actinopterygii: Agonidae). J Morphol 2020; 281:1018-1028. [PMID: 32621639 DOI: 10.1002/jmor.21223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 05/19/2020] [Accepted: 05/27/2020] [Indexed: 11/11/2022]
Abstract
Many vertebrates are armored over all or part of their body. The armor may serve several functional roles including defense, offense, visual display, and signal of experience/capability. Different roles imply different tradeoffs; for example, defensive armor usually trades resistance to attack for maneuverability. The poachers (Agonidae), 47 species of scorpaeniform fishes, are a useful system for understanding the evolution and function of armor due to their variety and extent of armoring. Using publically available CT-scan data from 27 species in 16 of 21 genera of poachers we compared the armor to axial skeletal in the mid body region. The ratio of average armor density to average skeleton density ranged from 0.77 to 1.17. From a defensive point of view, the total investment in mineralization (volume * average density) is more interesting. There was 10 times the material invested in the armor as in the endoskeleton in some small, smooth plated species, like Aspidophoroides olrikii. At the low end, some visually arresting species like Percis japonica, had ratios as low as 2:1. We categorized the extent and type (impact vs. abrasion) in 34 Agonopsis vulsa across all 35+ plates in the eight rows along the body. The ventral rows show abrasive damage along the entire length of the fish that gets worse with age. Impact damage to head and tail plates gets more severe and occurs at higher rates with age. The observed damage rates and the large investment in mineralization of the armor suggest that it is not just for show, but is a functional defensive structure. We cannot say what the armor is defense against, but the abrasive damage on the ventrum implies their benthic lifestyle involves rubbing on the substrate. The impact damage could result from predatory attacks or from intraspecific combat.
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Affiliation(s)
- Sebastian Kruppert
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
| | - Fabien Chu
- University of Washington, Seattle, Washington, USA
| | - Morgan C Stewart
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA.,W.M. Keck Science Department, Claremont McKenna, Scripps, and Pitzer Colleges, Claremont McKenna, California, USA
| | - Lars Schmitz
- W.M. Keck Science Department, Claremont McKenna, Scripps, and Pitzer Colleges, Claremont McKenna, California, USA
| | - Adam P Summers
- Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA
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9
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Izhar R, Gilboa C, Ben‐Ami F. Disentangling the steps of the infection process responsible for juvenile disease susceptibility. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Rony Izhar
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - Chen Gilboa
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
| | - Frida Ben‐Ami
- School of Zoology George S. Wise Faculty of Life Sciences Tel Aviv University Tel Aviv Israel
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10
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An alternative route of bacterial infection associated with a novel resistance locus in the Daphnia-Pasteuria host-parasite system. Heredity (Edinb) 2020; 125:173-183. [PMID: 32561843 PMCID: PMC7490384 DOI: 10.1038/s41437-020-0332-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 06/07/2020] [Accepted: 06/07/2020] [Indexed: 11/23/2022] Open
Abstract
To understand the mechanisms of antagonistic coevolution, it is crucial to identify the genetics of parasite resistance. In the Daphnia magna–Pasteuria ramosa host–parasite system, the most important step of the infection process is the one in which P. ramosa spores attach to the host’s foregut. A matching-allele model (MAM) describes the host–parasite genetic interactions underlying attachment success. Here we describe a new P. ramosa genotype, P15, which, unlike previously studied genotypes, attaches to the host’s hindgut, not to its foregut. Host resistance to P15 attachment shows great diversity across natural populations. In contrast to P. ramosa genotypes that use foregut attachment, P15 shows some quantitative variation in attachment success and does not always lead to successful infections, suggesting that hindgut attachment represents a less-efficient infection mechanism than foregut attachment. Using a Quantitative Trait Locus (QTL) approach, we detect two significant QTLs in the host genome: one that co-localizes with the previously described D. magna PR locus of resistance to foregut attachment, and a second, major QTL located in an unlinked genomic region. We find no evidence of epistasis. Fine mapping reveals a genomic region, the D locus, of ~13 kb. The discovery of a second P. ramosa attachment site and of a novel host-resistance locus increases the complexity of this system, with implications for both for the coevolutionary dynamics (e.g., Red Queen and the role of recombination), and for the evolution and epidemiology of the infection process.
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11
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Li R, Meng Q, Huang J, Wang S, Sun J. MMP-14 regulates innate immune responses to Eriocheir sinensis via tissue degradation. FISH & SHELLFISH IMMUNOLOGY 2020; 99:301-309. [PMID: 32061873 DOI: 10.1016/j.fsi.2020.02.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/08/2020] [Accepted: 02/12/2020] [Indexed: 06/10/2023]
Abstract
Matrix metalloproteinases (MMPs) are a cluster of enzymes that degrade the extracellular matrix (ECM) and some intracellular proteins; as such, they play an important role in tissue regeneration, infant growth, animal reproduction, and immunity. Most research into MMPs focuses mainly on their effects on the mammalian immune system. However, it is not clear how MMPs affect immune processes in crustaceans. Here, we cloned the open reading frame (ORF) of Eriocheir sinensis (Chinese mitten crab) MMP-14 (EsMMP-14) to explore the role of MMPs in crustacean innate immune responses. RT-PCR results showed that stimulation of crab with LPS and poly I:C upregulated expression of EsMMP-14 markedly. Besides, following the stimulation of 20-Hydroxyecdysone, the expression level of EsMMP-14 increased robustly, suggesting that EsMMP-14 involved in the molt process of E. sinensis. Hematoxylin and eosin staining of hepatopancreas and intestine revealed that knocking down EsMMP-14 maintained morphology following infection by Bacillus thuringiensis. Moreover, downregulated expression of EsMMP-14 increased the survival rate of infected E. sinensis. These results show that EsMMP-14 plays a role in innate immune responses of E. sinensis and fills a gap in our knowledge about the function of MMPs in crustaceans.
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Affiliation(s)
- Ran Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin, 300387, People's Republic of China
| | - Qinghao Meng
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin, 300387, People's Republic of China
| | - Jinwei Huang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin, 300387, People's Republic of China
| | - Shen Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin, 300387, People's Republic of China
| | - Jinsheng Sun
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Science, Tianjin Normal University, Tianjin, 300387, People's Republic of China.
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12
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Rossato JM, Moresco TR, Uczay J, da Rocha JBT. Staphylococcus aureus-induced sepsis in the lobster cockroach Nauphoeta cinerea. Comp Immunol Microbiol Infect Dis 2019; 66:101343. [PMID: 31446196 DOI: 10.1016/j.cimid.2019.101343] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/30/2019] [Accepted: 08/06/2019] [Indexed: 11/28/2022]
Abstract
Invertebrates have been instrumental in understanding the mechanisms involved in infectious diseases, considering the idea to replace, reduce and refine the use of mammals as well as to understand the basic principles of immune response in insect. We evaluated the consequences of Staphylococcus aureus-induced sepsis in the last instar nymphs of Nauphoeta cinerea injected with different concentrations of bacteria preserved in two culture media. Infected groups had a decrease in hemolymph metabolites (glucose, amino acids, total proteins, and cholesterol), in contrast to the proteins in the fat body. Higher concentrations of S. aureus caused permanent morphological alterations in adults, decrease in food consumption, increase in isolation, and increase in CFU until death of the cockroaches. Survival and protection of nymphs against a repeated and stronger challenge with the same bacteria varied according to the medium they were conserved. N. cinerea proves to be a suitable and promising model for studies related to bacterial infections.
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Affiliation(s)
- Juliana Marzari Rossato
- Departamento de Bioquímica e Biologia Molecular e Programa de Pós-graduação Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Brazil.
| | - Terimar Ruoso Moresco
- Departamento de Ciências da Saúde, Laboratório de Microbiologia CEMICRO, UFSM, Brazil.
| | - Juliano Uczay
- Departamento de Ciências da Saúde, Laboratório de Microbiologia CEMICRO, UFSM, Brazil.
| | - João Batista Teixeira da Rocha
- Departamento de Bioquímica e Biologia Molecular e Programa de Pós-graduação Bioquímica Toxicológica, Universidade Federal de Santa Maria (UFSM), Brazil.
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Liu C, Gibson AK, Timper P, Morran LT, Tubbs RS. Rapid change in host specificity in a field population of the biological control organism Pasteuria penetrans. Evol Appl 2019; 12:744-756. [PMID: 30976307 PMCID: PMC6439493 DOI: 10.1111/eva.12750] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 11/21/2018] [Accepted: 11/28/2018] [Indexed: 12/29/2022] Open
Abstract
In biological control, populations of both the biological control agent and the pest have the potential to evolve and even to coevolve. This feature marks the most powerful and unpredictable aspect of biological control strategies. In particular, evolutionary change in host specificity of the biological control agent could increase or decrease its efficacy. Here, we tested for change in host specificity in a field population of the biological control organism Pasteuria penetrans. Pasteuria penetrans is an obligate parasite of the plant parasitic nematodes Meloidogyne spp., which are major agricultural pests. From 2013 through 2016, we collected yearly samples of P. penetrans from eight plots in a field infested with M. arenaria. Plots were planted either with peanut (Arachis hypogaea) or with a rotation of peanut and soybean (Glycine max). To detect temporal change in host specificity, we tested P. penetrans samples annually for their ability to attach to (and thereby infect) four clonal lines of M. arenaria. After controlling for temporal variation in parasite abundance, we found that P. penetrans from each of the eight plots showed temporal variation in their attachment specificity to the clonal host lines. The trajectories of change in host specificity were largely unique to each plot. This result suggests that local forces, at the level of individual plots, drive change in specificity. We hypothesize that coevolution with local M. arenaria hosts may be one such force. Lastly, we observed an overall reduction in attachment rate with samples from rotation plots relative to samples from peanut plots. This result may reflect lower abundance of P. penetrans under crop rotation, potentially due to suppressed density of host nematodes. As a whole, the results show local change in specificity on a yearly basis, consistent with evolution of a biological control organism in its ability to infect and suppress its target pest.
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Affiliation(s)
- Chang Liu
- Department of Plant PathologyUniversity of GeorgiaTiftonGeorgia
| | | | | | | | - R. Scott Tubbs
- Crop and Soil Sciences, College of Agricultural and Environmental SciencesUniversity of GeorgiaTiftonGeorgia
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14
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Vigneron A, Jehan C, Rigaud T, Moret Y. Immune Defenses of a Beneficial Pest: The Mealworm Beetle, Tenebrio molitor. Front Physiol 2019; 10:138. [PMID: 30914960 PMCID: PMC6422893 DOI: 10.3389/fphys.2019.00138] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 02/07/2019] [Indexed: 12/04/2022] Open
Abstract
The mealworm beetle, Tenebrio molitor, is currently considered as a pest when infesting stored grains or grain products. However, mealworms are now being promoted as a beneficial insect because their high nutrient content makes them a viable food source and because they are capable of degrading polystyrene and plastic waste. These attributes make T. molitor attractive for mass rearing, which may promote disease transmission within the insect colonies. Disease resistance is of paramount importance for both the control and the culture of mealworms, and several biotic and abiotic environmental factors affect the success of their anti-parasitic defenses, both positively and negatively. After providing a detailed description of T. molitor's anti-parasitic defenses, we review the main biotic and abiotic environmental factors that alter their presentation, and we discuss their implications for the purpose of controlling the development and health of this insect.
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Affiliation(s)
- Aurélien Vigneron
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Charly Jehan
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Thierry Rigaud
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
| | - Yannick Moret
- UMR CNRS 6282 BioGéoSciences, Équipe Écologie Évolutive, Université Bourgogne-Franche Comté, Dijon, France
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15
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Cuellar-Gempeler C, Leibold MA. Multiple colonist pools shape fiddler crab-associated bacterial communities. THE ISME JOURNAL 2018; 12:825-837. [PMID: 29362507 PMCID: PMC5864236 DOI: 10.1038/s41396-017-0014-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 10/06/2017] [Accepted: 10/24/2017] [Indexed: 01/22/2023]
Abstract
Colonization is a key component of community assembly because it continuously contributes new species that can potentially establish and adds individuals to established populations in local communities. Colonization is determined by the regional species pool, which is typically viewed as stable at ecological time scales. Yet, many natural communities including plants, birds and microbes, are exposed to several distinct and dynamic sources of colonists and how multiple colonist pools interact to shape local communities remains unclear. Using a 16S rRNA amplicon survey, we profiled bacteria within surface, subsurface and burrow sediments and assessed their role as colonist pools for fiddler crab-associated bacteria. We found significant differences in composition among sediment types, driven by halophilic taxa in the surface, and different Desulfobacteraceae taxa in the subsurface and burrow. Bacteria from burrow sediment colonized the crab carapace whereas gut bacterial communities were colonized by burrow and surface sediment bacteria. Despite distinct colonist pools influencing gut bacteria, variation in composition across gut samples did not lead to significant clusters. In contrast, carapace bacterial communities clustered in six distinct groups loosely associated with crab species. Our findings suggest that multiple colonist pools can influence local communities but factors explaining variation in community composition depend on local habitats. Recognizing multiple colonist pools expands our understanding of the interaction between regional and local processes driving community structure and diversity.
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Affiliation(s)
- Catalina Cuellar-Gempeler
- Department of Biological Sciences, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32304, USA.
| | - Mathew A Leibold
- Section of Integrative Biology, University of Texas at Austin, 1 University Station C0930, Austin, TX, 78712, USA
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16
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Thompson O, Gipson SAY, Hall MD. The impact of host sex on the outcome of co-infection. Sci Rep 2017; 7:910. [PMID: 28424526 PMCID: PMC5430432 DOI: 10.1038/s41598-017-00835-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 03/13/2017] [Indexed: 11/27/2022] Open
Abstract
Males and females vary in many characteristics that typically underlie how well a host is able to fight infection, such as body-size, immune capacity, or energy availability. Although well studied in the context of sexual signalling, there is now growing recognition that these differences can influence aspects of pathogen evolution as well. Here we consider how co-infection between multiple pathogen strains is shaped by male-female differences. In natural populations, infections by more than one pathogen strain or species are believed to be a widespread occurrence. Using the water flea, Daphnia magna, we exposed genetically identical males and females to replicated bacterial co-infections. We found that pathogen transmission and virulence were much higher in females. However, males did not simply lower average pathogen fitness, but rather the influence of co-infection was more varied and less defined than in females. We discuss how pathogens may have more fitness benefits to gain, and consequently to lose, when infecting one sex over the other.
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Affiliation(s)
- Olivia Thompson
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Stephen A Y Gipson
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia
| | - Matthew D Hall
- School of Biological Sciences, Monash University, Melbourne, Victoria, 3800, Australia.
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17
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Ebert D, Duneau D, Hall MD, Luijckx P, Andras JP, Du Pasquier L, Ben-Ami F. A Population Biology Perspective on the Stepwise Infection Process of the Bacterial Pathogen Pasteuria ramosa in Daphnia. ADVANCES IN PARASITOLOGY 2015; 91:265-310. [PMID: 27015951 DOI: 10.1016/bs.apar.2015.10.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The infection process of many diseases can be divided into series of steps, each one required to successfully complete the parasite's life and transmission cycle. This approach often reveals that the complex phenomenon of infection is composed of a series of more simple mechanisms. Here we demonstrate that a population biology approach, which takes into consideration the natural genetic and environmental variation at each step, can greatly aid our understanding of the evolutionary processes shaping disease traits. We focus in this review on the biology of the bacterial parasite Pasteuria ramosa and its aquatic crustacean host Daphnia, a model system for the evolutionary ecology of infectious disease. Our analysis reveals tremendous differences in the degree to which the environment, host genetics, parasite genetics and their interactions contribute to the expression of disease traits at each of seven different steps. This allows us to predict which steps may respond most readily to selection and which steps are evolutionarily constrained by an absence of variation. We show that the ability of Pasteuria to attach to the host's cuticle (attachment step) stands out as being strongly influenced by the interaction of host and parasite genotypes, but not by environmental factors, making it the prime candidate for coevolutionary interactions. Furthermore, the stepwise approach helps us understanding the evolution of resistance, virulence and host ranges. The population biological approach introduced here is a versatile tool that can be easily transferred to other systems of infectious disease.
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Affiliation(s)
- Dieter Ebert
- Zoological Institute, University of Basel, Basel, Switzerland
| | - David Duneau
- Zoological Institute, University of Basel, Basel, Switzerland; Department Ecologie et Diversité Biologique, University Paul Sabatier-Toulouse III, Toulouse, France
| | - Matthew D Hall
- Zoological Institute, University of Basel, Basel, Switzerland; Monash University, School of Biological Sciences, Clayton Campus, Melbourne, VIC, Australia
| | - Pepijn Luijckx
- Zoological Institute, University of Basel, Basel, Switzerland; Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Jason P Andras
- Zoological Institute, University of Basel, Basel, Switzerland; Department of Biological Sciences, Mount Holyoke College, South Hadley, MA, USA
| | | | - Frida Ben-Ami
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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18
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Brinton BA, Curran MC. The Effect of Temperature on Synchronization of Brood Development of the Bopyrid Isopod Parasite Probopyrus pandalicola with Molting of Its Host, the Daggerblade Grass Shrimp Palaemonetes pugio. J Parasitol 2015; 101:398-404. [PMID: 25826017 DOI: 10.1645/14-599.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The bopyrid isopod Probopyrus pandalicola is a hematophagous ectoparasite that sexually sterilizes some palaemonid shrimps, including female daggerblade grass shrimp Palaemonetes pugio. The reproduction of parasitic isopods is thought to occur synchronously with host molting because the brood would be unsuccessful if molting occurred before the larvae were free swimming. Temperature affects the length of the molting cycle of shrimp, and therefore may also affect the incubation time of isopod broods. The purpose of the present study was to determine the effect of temperature on brood development of the parasite and on the degree of synchronization with the molting of its host. Parasitized P. pugio were monitored daily at 2 experimental temperatures, 23 and 15 C, in temperature-controlled chambers for the duration of a full parasite reproductive cycle. Developmental stage was determined by the visible coloration of the brood through the exoskeleton of the host, and was designated as egg, embryo I, embryo II, or epicaridium larvae. Temperature significantly affected median brood incubation time, which was only 11 days at 23 C, as compared to 35 days at 15 C. The final developmental stage (epicaridium larvae) was 3 times shorter at 23 C (median 3 days; n = 45) than at 15 C (median 9 days; n = 15). Temperature significantly affected the intermolt period of parasitized shrimp, which was shorter at 23 C (median 12 days) than at 15 C (median 37 days). A smaller percentage of the intermolt period elapsed between larval release and shrimp molting at 23 C (0.0%) than at 15 C (3.1%), indicating closer synchronization between host molting and parasite reproduction at the warmer temperature. At 15 C, the isopods utilized a smaller proportion of the time that was available for brood incubation during the intermolt period of their host. Brood size ranged from 391 to 4,596 young and was positively correlated with parasite and host size. Because development progressed more rapidly at 23 C, warmer temperatures could increase the prevalence of P. pandalicola. The corresponding reduction in the abundance of ovigerous grass shrimp as a result of sexual sterilization by bopyrids could adversely impact estuarine ecosystems, as grass shrimp are a crucial link in transferring energy from detritus to secondary consumers.
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Affiliation(s)
- Brigette A Brinton
- Box 20467, Department of Marine and Environmental Sciences, Savannah State University, Savannah, Georgia 31404
| | - Mary Carla Curran
- Box 20467, Department of Marine and Environmental Sciences, Savannah State University, Savannah, Georgia 31404
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19
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Izhar R, Ben-Ami F. Host age modulates parasite infectivity, virulence and reproduction. J Anim Ecol 2015; 84:1018-28. [PMID: 25661269 DOI: 10.1111/1365-2656.12352] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 01/24/2015] [Indexed: 01/15/2023]
Abstract
Host age is one of the most striking differences among hosts within most populations, but there is very little data on how age-dependent effects impact ecological and evolutionary dynamics of both the host and the parasite. Here, we examined the influence of host age (juveniles, young and old adults) at parasite exposure on host susceptibility, fecundity and survival as well as parasite transmission, using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa. Younger D. magna were more susceptible to infection than older ones, regardless of host or parasite clone. Also, younger-infected D. magna became castrated faster than older hosts, but host and parasite clone effects contributed to this trait as well. Furthermore, the early-infected D. magna produced considerably more parasite transmission stages than late-infected ones, while host age at exposure did not affect virulence as it is defined in models (host mortality). When virulence is defined more broadly as the negative effects of infection on host fitness, by integrating the parasitic effects on host fecundity and mortality, then host age at exposure seems to slide along a negative relationship between host and parasite fitness. Thus, the virulence-transmission trade-off differs strongly among age classes, which in turn affects predictions of optimal virulence. Age-dependent effects on host susceptibility, virulence and parasite transmission could pose an important challenge for experimental and theoretical studies of infectious disease dynamics and disease ecology. Our results present a call for a more explicit stage-structured theory for disease, which will incorporate age-dependent epidemiological parameters.
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Affiliation(s)
- Rony Izhar
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Frida Ben-Ami
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
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20
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Ohmer ME, Cramp RL, White CR, Franklin CE. Skin sloughing rate increases with chytrid fungus infection load in a susceptible amphibian. Funct Ecol 2014. [DOI: 10.1111/1365-2435.12370] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michel E.B. Ohmer
- School of Biological Sciences The University of Queensland St. Lucia Qld 4072 Australia
| | - Rebecca L. Cramp
- School of Biological Sciences The University of Queensland St. Lucia Qld 4072 Australia
| | - Craig R. White
- School of Biological Sciences The University of Queensland St. Lucia Qld 4072 Australia
| | - Craig E. Franklin
- School of Biological Sciences The University of Queensland St. Lucia Qld 4072 Australia
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21
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Routtu J, Ebert D. Genetic architecture of resistance in Daphnia hosts against two species of host-specific parasites. Heredity (Edinb) 2014; 114:241-8. [PMID: 25335558 DOI: 10.1038/hdy.2014.97] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Revised: 08/21/2014] [Accepted: 08/27/2014] [Indexed: 02/04/2023] Open
Abstract
Understanding the genetic architecture of host resistance is key for understanding the evolution of host-parasite interactions. Evolutionary models often assume simple genetics based on few loci and strong epistasis. It is unknown, however, whether these assumptions apply to natural populations. Using a quantitative trait loci (QTL) approach, we explore the genetic architecture of resistance in the crustacean Daphnia magna to two of its natural parasites: the horizontally transmitted bacterium Pasteuria ramosa and the horizontally and vertically transmitted microsporidium Hamiltosporidium tvaerminnensis. These two systems have become models for studies on the evolution of host-parasite interactions. In the QTL panel used here, Daphnia's resistance to P. ramosa is controlled by a single major QTL (which explains 50% of the observed variation). Resistance to H. tvaerminnensis horizontal infections shows a signature of a quantitative trait based in multiple loci with weak epistatic interactions (together explaining 38% variation). Resistance to H. tvaerminnensis vertical infections, however, shows only one QTL (explaining 13.5% variance) that colocalizes with one of the QTLs for horizontal infections. QTLs for resistance to Pasteuria and Hamiltosporidium do not colocalize. We conclude that the genetics of resistance in D. magna are drastically different for these two parasites. Furthermore, we infer that based on these and earlier results, the mechanisms of coevolution differ strongly for the two host-parasite systems. Only the Pasteuria-Daphnia system is expected to follow the negative frequency-dependent selection (Red Queen) model. How coevolution works in the Hamiltosporidium-Daphnia system remains unclear.
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Affiliation(s)
- J Routtu
- Zoologisches Institut, Universität Basel, Basel, Switzerland
| | - D Ebert
- Zoologisches Institut, Universität Basel, Basel, Switzerland
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22
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Bacterial epibionts of Daphnia: a potential route for the transfer of dissolved organic carbon in freshwater food webs. ISME JOURNAL 2014; 8:1808-19. [PMID: 24694716 DOI: 10.1038/ismej.2014.39] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 02/06/2014] [Accepted: 02/12/2014] [Indexed: 11/09/2022]
Abstract
The identification of interacting species and elucidation of their mode of interaction may be crucial to understand ecosystem-level processes. We analysed the activity and identity of bacterial epibionts in cultures of Daphnia galeata and of natural daphnid populations. Epibiotic bacteria incorporated considerable amounts of dissolved organic carbon (DOC), as estimated via uptake of tritiated leucine: three times more tracer was consumed by microbes on a single Daphnia than in 1 ml of lake water. However, there was virtually no incorporation if daphnids were anaesthetised, suggesting that their filtration activity was essential for this process. Microbial DOC uptake could predominantly be assigned to microbes that were located on the filter combs of daphnids, where the passage of water would ensure a continuously high DOC supply. Most of these bacteria were Betaproteobacteria from the genus Limnohabitans. Specifically, we identified a monophyletic cluster harbouring Limnohabitans planktonicus that encompassed sequence types from D. galeata cultures, from the gut of Daphnia magna and from daphnids of Lake Zurich. Our results suggest that the epibiotic growth of bacteria related to Limnohabitans on Daphnia spp. may be a widespread and rather common phenomenon. Moreover, most of the observed DOC flux to Daphnia in fact does not seem to be associated with the crustacean biomass itself but with its epibiotic microflora. The unexplored physical association of daphnids with heterotrophic bacteria may have considerable implications for our understanding of carbon transfer in freshwater food webs, that is, a trophic 'shortcut' between microbial DOC uptake and predation by fish.
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Jansen M, Vergauwen L, Vandenbrouck T, Knapen D, Dom N, Spanier KI, Cielen A, De Meester L. Gene expression profiling of three different stressors in the water flea Daphnia magna. ECOTOXICOLOGY (LONDON, ENGLAND) 2013; 22:900-914. [PMID: 23564370 DOI: 10.1007/s10646-013-1072-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/29/2013] [Indexed: 06/02/2023]
Abstract
Microarrays are an ideal tool to screen for differences in gene expression of thousands of genes simultaneously. However, often commercial arrays are not available. In this study, we performed microarray analyses to evaluate patterns of gene transcription following exposure to two natural and one anthropogenic stressor. cDNA microarrays compiled of three life stage specific and three stressor-specific EST libraries, yielding 1734 different EST sequences, were used. We exposed juveniles of the water flea Daphnia magna for 48, 96 and 144 h to three stressors known to exert strong selection in natural populations of this species i.e. a sublethal concentration of the pesticide carbaryl, infective spores of the endoparasite Pasteuria ramosa, and fish predation risk mimicked by exposure to fish kairomones. A total of 148 gene fragments were differentially expressed compared to the control. Based on a PCA, the exposure treatments were separated into two main groups based on the extent of the transcriptional response: a low and a high (144 h of fish or carbaryl exposure and 96 h of parasite exposure) stress group. Firstly, we observed a general stress-related transcriptional expression profile independent of the treatment characterized by repression of transcripts involved in transcription, translation, signal transduction and energy metabolism. Secondly, we observed treatment-specific responses including signs of migration to deeper water layers in response to fish predation, structural challenge of the cuticle in response to carbaryl exposure, and disturbance of the ATP production in parasite exposure. A third important conclusion is that transcription expression patterns exhibit stress-specific changes over time. Parasite exposure shows the most differentially expressed gene fragments after 96 h. The peak of differentially expressed transcripts came only after 144 h of fish exposure, while carbaryl exposure induced a more stable number of differently expressed gene fragments over time.
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Affiliation(s)
- Mieke Jansen
- Laboratory of Aquatic Ecology, Evolution and Conservation, Catholic University of Leuven, Charles Deberiotstraat 32, 3000 Leuven, Belgium.
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